Theme 2: Emerging Technology for Observations Panel 2.3: Leveraging existing networks and mobile devices ARM, NEON, smartphones, cars, planes, etc.

Transcription

1 Leveraging Air Quality Observing Systems in the United States: An Approach to Addressing Operational Gaps and Earth System Science Challenges Related to Atmospheric Composition and Dynamics Theme 2: Emerging Technology for Observations Panel 2.3: Leveraging existing networks and mobile devices ARM, NEON, smartphones, cars, planes, etc. Jim Szykman, U.S. EPA + others Lukas Valin, Rohit Mathur, Russell Long, Kevin Cavender U.S. EPA Jim Crawford, Barry Lefer, Bob Swap NASA Kelly Chance Smithsonian Astrophysical Observatory Ruben Delgado UMBC WORKSHOP ON THE FUTURE OF ATMOSPHERIC BOUNDARY LAYER OBSERVATIONS October 24 26, 2017 Airlie House Warrenton, VA

2 Ambient Air Monitoring Stations in the US Network intended to determine state/tribe compliance with health and secondary (e.g., visibility) standards Addressing the most intractable pollution issues demands better integration of network with rigorous scientific standards. Aggregate map of the majority of routine U.S. monitoring stations, illustrating relatively broad coverage across the continental United States. Note spatial gaps in sparsely populated areas. Working with bridging state AQ management staff with EPA and NASA research team on one segment of network, PAMS, hopefully providing roadmap for further collaboration of federal agencies on other state networks

3 EPA Photochemical Assessment Monitoring Station (PAMS) Network PAMS Network established as a result of 1990 Clean Air Act Amendments (CAAA) to better understand high O 3 locations. The 2015 revision of the O3 National Ambient Air Quality Standard from 75 ppb to 70 ppb includes changes that will result in: A Broader and less dense network, merged with NCORE network with a large set of required measurements. A requirement for states to propose additional Enhanced Monitoring Plans, to better understand the local O 3 problem. PAMS merged with NCORE NO, NO 2, hourly VOC (or high sensitivity HCHO), NOy, O 3 (year round). SO 2, ppb precision CO, PM 2.5 mass and speciation (At least 1 in 3 day), PM 2.5 continuous, PM mass, basic met. parameters, mixed layer height (via ceilometers/lidar/profilers) Ground Based Spectrometers column NO 2, HCHO, O 3, and SO 2 via collaboration with NASA PAMS Network Present (blue green circles) Future 2019 (green)

4 Leveraging Large and Small Research Efforts to inform Boundary Layer Measurements with EPA Networks DISCOVER-AQ: Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality Multi-year mission: Overall Goal - How can ambient air quality be reliably informed using non-traditional approaches, such as satellite remote sensing? EPA research used to inform: Evaluation of emerging measurements technology (in-situ, small sensors, and remote sensing) for use in AQ Networks Evaluation and improvements for Community Multiscale Air Quality (CMAQ) fine-scale modeling ACES: Ad-hoc Ceilometer Evaluation Study Nov. 15-Dec. 16, UMBC (Catonsville, MD) : EPA/NWS/UMBC Measurements to help guide EPA PAMS program implementation for new hourly MLH requirement and supplement current efforts under NWS ceilometer test bed. Test ceilometer performance in low aerosol loading environment Focused on mixing layer height determination during morning and evening transition periods: MLH using available vendor software MLH using a common algorithm Denver, CO Observation Strategy July-August

5 ACES: Ad-hoc Ceilometer Evaluation Study Vaisala CL 51 Altitude (m) Leosphere Doppler Wind Lidar Time (UTC) Concurrent Multiple Instrument Evaluations provide Important Information for Technology Use in Operations Network Decisions Campbell Scientific CS135 Lufft CHM15k

6 Characterizing Nocturnal O 3 Aloft is Important Can Lower Cost Technology Fill a Critical Observational Gap? NOAA BAO Tower, CO: 2014 DISCOVER AQ Decoupling of BL from residual layer Well mixed BL WRAL Tower Observations, Raleigh, NC: 1996 Surface O 3 = Background [transport] + In situ production Transport constitutes a large fraction of night time O 3 in residual layer Local background influenced by downward mixing of O 3 from the residual layer Location of tall towers (> 400m) e folding distances aloft nocturnally are several hundred of kilometers Can existing tall structures be instrumented with lower cost sensors, O3 plus met, to provide a critical continuous aloft observation? ~20x20 array of aloft measurements [Wikipedia: List of tallest structures in the world meters]

7 Pandora Ground-Based Spectrometer System developed at NASA Goddard Extensive Use/Testing During DISCOVER AQ Solar source spectrometer ( nm: 0.6 nm resolution) column NO 2, O 3, HCH 2 O, and SO 2 every 80 second. 2 main parts to instrument (1) sensor head and (2) spectrometer, TE cooler, electronics, computer contained with environmental housing case 23 x16 x39 or 8 rack mounted enclosure. Can operate in DS, ZS and MAX DOAS modes and potentially provide information on vertical profiles. EPA and NASA are exploring deployment of Pandoras at PAMS as research instrument to provide improved characteriztion of emissions and serve as a U.S. groundbased satelltie validation network

8 Direct sun UV/Vis composition measurements capture large-eddy effects UV/Vis direct sun retrievals of NO 2 total column variations likely reflect large eddy influence. Potential for complementary information on formaldehyde and H 2 O. Nighttime integrations possible but will be slower, and require half-moon or more. For dual spectrometer Pandoras (version 2S), nighttime NO3 will be a product. Must consider influences of shear and viewing geometries. Herman et al.,

9 Combining surface and column NO 2 measurements reflects mixing depth Before 11 AM 1 ppb : 1e15 cm 2 > Assume well mixed PBL: Height 0.5 km After 1130 AM ~1 ppb : 3e15 cm 2 > Assume well mixed PBL Height 1.5 km BAO Tower CL51 The observed relationship of NO2 column (molecule cm 2 ) divided by surface concentration (molecule cm 3 ) places a constraint on boundary layer dynamics ( units of cm ) 9

10 Assessing Mixed Layer growth/mixing via atmospheric species Regress daily NO2 column vs surface concentration for each hour (colors) Y = Column (+ FreeTrop/Stratospheric NO2): Surface (x) Maximum observed slope at BAO Tower is 2.3x10 15 / 1ppb and occurs at 12 noon. 1 km average PBL Maximum R2 is 0.71 and also occurs at 12 PM. This is when mixing is most vigorous. 10

11 Parting Thoughts - Emerging Technology Leveraging Existing Network Forthcoming changes to EPA PAMS Network will increase the value of measurement suite at these sites to a larger community of interest. There is a need to better coordinate ABLH/MLH observations across operational networks; implementation of heterogeneous measurement technology will require research to harmonize the meaning/use of the measurements algorithms? Emerging trace gas measurements (surface to satellite) will likely provide a different perspective on BL dynamics; LES to large scale transport. Satellite trace gas retrievals for several species, NO2, HCHO, and SO2 very sensitive to profile shapes in BL. Better characterization of boundary layer needed for improved retrievals and assessing uncertainties TROPOMI and TEMPO. Improved trace gas measurements Ground based spectrometer Column density O 3, NO 2, HCHO, SO 2 Ceilometer/lidar Aerosol layers/mixing heights